const fp = require('lodash/fp')

const cars = [
    {name: 'Ferrari FF', horsepower: 660, dollar_value: 700000, in_stock: true},
    {name: 'Spyker c12 zagato', horsepower: 650, dollar_value: 648000, in_stock: false},
    {name: 'Jaguar XKR-S', horsepower: 550, dollar_value: 132000, in_stock: false},
    {name: 'Audi R8', horsepower: 525, dollar_value: 114200, in_stock: false},
    {name: 'Aston Martin One-77', horsepower: 750, dollar_value: 1850000, in_stock: true},
    {name: 'Pagani Huayra', horsepower: 700, dollar_value: 1300000, in_stock: false},
]

let islast = function (cars) {
    let last_car = fp.last(cars)
    return fp.prop('name', last_car)
}
// console.log(islast(cars));

let _average = function (xs) {
    return fp.reduce(fp.add, 0, xs) / xs.length
}
let averageDollarValue = function (cars) {
    let dollar_values = fp.map(function (car) {
        return car.dollar_value
    }, cars)
    console.log(dollar_values);
    return _average(dollar_values);
}

// console.log(averageDollarValue(cars));

// 1
const resultont = fp.flowRight(fp.prop('in_stock'), fp.last);
// console.log(resultont(cars));
// 2
const resulttwo = fp.flowRight(fp.prop('name'), fp.first);
// console.log(resulttwo(cars));
// 3
const resultthree = fp.flowRight(_average, fp.map('dollar_value'))
console.log(resultthree(cars));

let _underscore = fp.replace(/\W+/g, '_');
// sanitizeNames(["Hello World"]) => ["hello_world"]
//
let sanitizeNames = function (arr) {
    return fp.flowRight(_underscore, fp.toLower, fp.join('.', arr))
}

const array = ["Hello World"];
console.log(fp.join('.', array));
console.log(fp.toLower(_underscore(fp.join('.', array)))); // 此处打印机结果正常
// console.log(sanitizeNames(array)); // 此处打印一直报错 求解答
